Process and apparatus for drawing glass.



' J. H. LUBBERS.

PROCESS AND APPARATUS FOR DRAWING GLASS.

APPLICATION FILED NOV. 2, 1908.

926 501 Patented June 29,1909.

2 SHEETSSHEET 1.

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WITNESSES J. H. LUBBERS.

PROCESS AND APPARATUS FOB. DRAWING GLASS.

APPLICATION TILED NOV. 2, 1908.

'926,501 Patented June 29, 1909.

2 SHEETS-SHEET 2 J0 UNITED STATES PATENT OFFICE.

JOHN H. LUBBERS, O1" PlT'l SBURG, PEN \'SYLVANL\, ASSIUXOR TO \\'lNl)OW GLASS MACHINE COMPANY, ()l. IlT'lSBUliG, PENNSYLVANIA, A CORPORATION OF NllW JERSEY.

PROCESS AND APPARATUS FOR DRAW'ING GLASS.

Specification of Letters Patent.

Patented June 29, 1909.

Application filed November 2, 1908. Serial No. 460,561.

To all whom it may concern:

Be it known that l, .lonn ll. hummus, a citizen of the United States, residing at Pittshtng, in the State of Pennsylvania, have invented certain new and useful lmprovements in Processes and Apparatus for Drawing,- Glass, of which the following is a specification.

My invention relates to the art of mechanically forming glass articles, by drawing upward from a receptacle of molten glass, and its primary object is to render the product more uniform and to more easily ontrol the operation of drawine.

The invention illustrated in the accompanying drawings wherein Figure l is a side elevation and partial vertical section of one form of apparatus for carrying out the invention, and Fig. 2 is a 'lront: elevation of thc,same. Fig. 3 is a vertical central section ol certain parts of a modified apparatus, and Fig. 1 is a plan view of a drawing pot and l'urnace.

lit the practice ol this art, it has heen t'ound dillicult to make the glass of the same thickness throughout the. area oi a cylimlcr or sheet, and much trouhle has heen experienccd hy reason oi. the so-called thickand-thin glass. That is, in drawing cylinders for example, the glass is found to he thicker at one portion of the circumleronce than at another. It will be und rstood that, this objectionable on account of the hreakage to which it gives rise, hoth during the drawing and in subsequent treatnumt, on account of the difficulty of properly llaltening such a, glass when made from cylinders. on account of causing, waste in cutting, and l'or various other rcasons. l'lxpcricnce has shown that there are various causcs of this defe t. among which may he mentioned the factthat in ladlingr into a refractory pot. the consistency ot' thc glass may he dill'crent in dil'l'erent parts of thc pol; that the temperature of the pot itself may he dill'crcnt at different points on the sides: that the pot may he -out of level. so that th drawing depth is not. uniform over the area; the. character ol the materials in the walls 01' the pot may vary; and other causes ol various kinds may cau e the lliick-:||nl-lhin drawing of the glass. l l|a\c found that whatever the cause of the dillicnlty it may generally be corrc tcd hy adjusting the surface tension of the glass in the containing rcccptaclc:

and that this surface tension may be controlled hy varying the distance of the point of draw from the walls of the pot, at various points: in short, that when an article is being drawn thick-and-thin the fault can he corrected and the thickness made uniform. by adjusting the relative positions of the drawing pot and the drawing devices as the bait or blow pipe travels upward drawing the glass with it. The importance of this discovery will he appreciated from considering that the conditions under which glass drawing is carried on are almost certain to vary, and depend very largely upon the skill and familiarity of the workn'ien. For example, where glass is ladlcd l'roni tanks into drawing pots, one ladlcr may he accustomed to dipping out l'rom a certain locality in the mclling tank. while his successor on lhc ncxt shil't may he accustomed to dipping from a dill'crcnt locality. .\lso the character ol' thc glass in the pot is very dependent upon the way it is poured in hy the ladlcr. It is also dependent upon the condition of tho hcatinfi apparatus under the pot upon air currents, upon the po sition of the pot. and various other conditions involved in the optn'ation. For some time it was not mnlcrstood why one cylinder or sheet would draw corrtwtly and the next would he drawn thick and thin,-which ol'tcu llappcncd even with the same work- :ncn employed in the manipulation. l have l'ound however. that the thickness of the glass drawn up. in forming a. cylinder or 01' course the adjustment of relative positions of the containing receptacle for the molten glass and the dra .vin; mechanism can he made from time to time after its necessity hccomcs apparent from examining the product and while the actual drawing operation is not in progress: hut it is often dcsirahle to correct irregularities at once and during the drawing of the article. l llclt irregularities. particularly in drawing cylindcrs, can easily hc detected hy the eye as soon as the trap is Formed.

in l i; -s. l and 2. l show a drawin'g "arriagrc comprising a l'rannwith l\l( hat-s 3. L and top and hottom hars I5, "I provided with guide hlocks 5 which it will he undcrslood lllfi llt) travel over the vertical guide bars 6, as the frame is raised by any convenient means such as a cable 7 On this frame is a supporting bar 8 from which projects forwardly a hook 9, upon which the blow-pipe 10 is hung, whilethe lower end of the p1 e' rests in a slotted guide 11 and is steadiet by an intermediate spring 12. The bar 8 has rearwardly projecting rods 13, 14%,which are threaded'and, passing freely through horizontally elongated slots in the bars 3, 4C of the frame, are engaged by threaded sleeves 16. These sleeves are held against to-andfro motion by block 17,. engaging annular grooves 18 in the sleeve. At the same time the block 17 is slidable sidewise in guides 19 19 and for giving it lateral motion in either direction I may conveniently employ a screw 20 mounted in the block 21 on the frame, as shown in Fig. 2. These screws 20 have sprocket wheels 22, over which pass opcrating chains 24; and likewise the sleeves '16 have sprocket wheels 16"- provided with chains 23. Thus by turning the sleeves 16, the blowpipe and bait Wlll be gradually moved to and from the position of vertical alinement of the traveling frame 3, 4:: and by turning the screws 20 the bait and blowplpe will we laterally moved with. respect to the frame, so that by the combined motions the relative positions of the bait and the pot P containing the glass, may be adjusted in altering the distances of the drawin any direction. The sprockets 16 and 22 are moved by cords 23 -and 2a in pulleys on the shafts 16 and 20, and these cords referably hang down so that they are at times in easy reach of the operator, so that thus the adjustment can be'readily made at any time without interfering with the motion of the carriage and blow-pipe.

-As soon as the draw is started and the cap -'formed on the blow-pipe, the relative thickness at various parts of the cylinder circumference may easily be seen at the points marked wand 3/, Fig. l, and if the sides are not uniform the thickness is at once'adjusted by slowly manipulating the cords 23%", 24:, correcting the inequalities by point from the wall of the pot, thus changingthe area of the surface skin which 18 being drawn up to form the cylinder.

In Figs. 3 and l, lhave supposed the bait carriage for bait 1G to travel in a fixed vertical alinement; but thepotP is made adjustf able in position by reason of ,its bearings 25, 26, supported on base 27, being movable --"in any direction by the combined action of the screws 28 and 30, respectivel provided with hand-wheels 29 and'31, theearings of the screws 28 and 30 being slidably mounted by slots X.

It will be understood however; that I am not limited to any articular method or means for accomplishing the adjustment; it

may be done not only by changing the relative positions of pot'and bait, but by chang ing the level of the bottom of the pot, or varying temperature conditions either 111 the furnace or on the glass surface, etc. That is, any method or means for adjusting the surface tension of the glass from which an article is being drawn is within the scope of my invention. F or I believe I Was the first not only to discover that the surface tension may be varied by these relative movements and adjustments above described, but also the fact that thick-and-thin drawing wasdue to unequal surface tension, and could be corrected by adjusting the surface tension.

Having thus described my invention and illustrated its use, what I claim as new and desire to secure by Letters Patent, is the tolllowing:

1. in the process of drawing glass, the step which consists in adjusting the surface tension of the molten glass from which the article is drawn, during the progress of the draw, substantially as described.

2. in the process of drawing glass the step which consists in adjusting the surface tension of the mass of. molten glass during the drawing operation by changing tire relative positions of the glass containing vessel and the drawing bait, substantially as described.

In the art of drawing glass articles, the process of adjusting the surface tension to correctinequalities by changing the position of the drawing point with. relation to the sides of the vessel containing the molten glass, substantially as described.

at. In the art of drawing glasscylinders the process of adjusting and equalizing the thickness around the circumference by alteringthe distance of the drawing position from the walls of the vessel containing the molten glass during the progress of the draw, substantially described.

5. In glass drawing apparatus, a glassholding receptacle, and a drawing device, said parts being mounted for lateral adjustment, relative to each other, and means to eiiect the adjustment without stopping the drawing motion, substantially as described.

6. 1;? glass drawing ap aratus, the combination with a glass hol ing receptacle, of

a drawing device and means'to adjust Said device laterally relatively to the receptacle while it is in motion, substantially as described.

7. Glass drawing apparatus comprism meansfor adjusting the relative positions 0 i the glass containing receptacle and the-drawmg devices during and without interrupting the motion of the latter, substantially asidescribed. r

8. The combination with a receptacle fo 7 conta ning molten glass, and devicesjfor drawing an article upward therefrom, of their motion llllWiH'k'l 1'1'0111 U111 body 01' glass, 10 111011115 for adjusti11gl'l1e surface t1'111si011 01" substantially as (lui :ril.1v l. 111i: 1110111 11 glass during the drawing opcra- I11 testimony \rhrrcol' l ham hereuntxr U011, milmlantially as described. I, i signed my name in the presence 01 the two 9. 111 apparatus for drawing glass arlisalhscrilml witnesses. cl'es, 111ca11s 1111- adjusting the surface tel-1511 11 JOHN H. LUBBERS. of the body of molten glass being drawn from, cmnprising 11'1ecl'1a11is111 to relatively more the drawing devices laterally during "itnesses [11. M. Conwm, (i. B.- BLEYMING. 

